Thousands of Russian opposition activists have marched through Moscow denouncing President Vladimir Putin's rule and calling for the release of those they consider political prisoners.
Police said about 6,000 people took part in the protest on June 12, which was timed to coincide with the Russia Day state holiday. Correspondents at the scene said around 10,000 took part.
The marchers headed to Moscow's central Bolotnaya Square, where protests against Putin's return to the Kremlin last year ended in violence.
Protesters carried pictures and banners in support of activists detained after the May 6, 2012, protest, on the eve of Putin's inauguration to a third term as president.
Twenty-seven people face charges over what authorities call "mass rioting" during that protest. Preliminary hearings against 12 of the accused began earlier this month.
Critics say the "Bolotnaya case" trials are part of an unprecedented crackdown against the opposition since Putin's return to the presidency.
Protesters chanted slogans against Putin and for freedom as they marched on June 12.
'For Our And Your Freedom'
Lydia, a pensioner from Moscow, told an RFE/RL correspondent that innocent people were thrown behind bars after last year's protest.
"First of all, we want Moscow to really belong to Muscovites. That is first," she said.
"Secondly, it has been a full year since the May 6 [Bolotnaya case] prisoners are behind bars for nothing at all. [That rioting] was a pure provocation by, let's say, the authorities of the Interior Ministry, by Putin. I believe they must be set free."
The protest action was branded a "march for our and your freedom," a slogan very popular among Soviet-era dissidents in Russia.
Opposition leader and anticorruption blogger Aleksei Navalny and other opposition politicians led the march.
Navalny is standing trial on embezzlement charges that he says are Putin's revenge for his activism.
There were no reports of major incidents on June 12.
Opposition activists in St.Petersburg distributed leaflets in support of detained opposition activists.
With reporting by Interfax